I'll assume a 2P game
63 Golds. Which is more than the entire pile.
Have a hand of Forge, 10xCultist, 20xRats, 2xOvergrown Estate, 10xMarket Square, 1x Watchtower. Have an empty deck/discard otherwise.
Forge the Cultists, Rats, and Overgrown Estates. Reveal all 10 MS. Trash Gained Golds with Watchtower. Continue this process of drawing and revealing MS all 52 times. Gain 62 Golds.
If you drop the price of Gold to $0, then you could even Forged all of those into a Gold, for a 63rd.